The only one I could think of would be garter snakes...and even then they only come together for breeding. The basic bottom line is that no snake species is really social with partners or groups. To keep snakes healthy and happy, no matter what kind, keep one snake per enclosure.

Problems with co-habitation abound: Stress from domination issues that leads to non-feeding snakes, Never knowing which snake is the sick one, Potential violent behavior including the odd act of cannibalism... All in all it's just not worth it to try housing together.